"To be honest, it still makes me uncomfortable to talk about it," Gomez said. "I feel I'm able to reach my fans and understand people when I am one on one and they're dealing with the same thing because I've been there. I'm trying to take something that's negative and turn it into a positive."

As for prepping for her upcoming tour, Selena said, "I gotta be healthy -- I shouldn't eat the things I do eat."

See throwback photos of Selena Gomez and Demi Lovato:

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Selena Gomez and Demi Lovato, throwback pics

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Selena Gomez is 'trying to turn a negative into a positive' with lupus diagnosis

DISNEY'S FRIENDS FOR CHANGE: PROJECT GREEN - April 4, 2009 - Disney stars Miley Cyrus, Selena Gomez, the Jonas Brothers and Demi Lovato are among the 29 young stars participating in Disney's Friends for Change: Project Green (www.Disney.com), a multiplatform environmental initiative that invites kids to join together to help the environment across four key areas: climate, water, waste and habitats. Kids will learn practical ways to preserve the planet, track their collective impact and have the opportunity to vote on how $1 million in donations from Disney will be divided and invested in various environmental causes over the course of a year. The messages will air on Disney Channel, Disney XD, Radio Disney and Disney.com beginning FRIDAY, MAY 15, 2009. (Photo by Jaimie Trueblood/Disney Channel/ABC via Getty Images)
DEMI LOVATO; SELENA GOMEZ;MILEY CYRUS

TORONTO, ON - JUNE 18: Actresses Demi Lovato and Selena Gomez (R) attend the Red Carpet Premiere For Disney's 'Princess Protection Program' at the Queen Elizabeth Theatre on June 18, 2009 in Toronto, Canada. (Photo by George Pimentel/WireImage)

Actresses Selena Gomez and Demi Lovato attend the 2009 American Music Awards at Nokia Theatre L.A. Live on November 22, 2009 in Los Angeles, California.